add `doom/large-file-check to prompt literal open of large files

core/autoload/editor.el

@@ -206,3 +206,17 @@ for function signatures or notes. Run again to clear the header line."
                     (setq content (replace-regexp-in-string "\n" " " content t t))
                     (setq content (replace-regexp-in-string "\\s-+" " " content))
                     content)))))
+
+;;;###autoload
+(defun doom/check-large-file ()
+  (let* ((filename (buffer-file-name))
+         (size (nth 7 (file-attributes filename))))
+    (when (and
+           (not (memq major-mode doom-large-file-modes-list))
+           size (> size (* 1024 1024 doom-large-file-size))
+           (y-or-n-p (format (concat "%s is a large file, open literally to "
+                                     "avoid performance issues?")
+                             filename)))
+      (setq buffer-read-only t)
+      (buffer-disable-undo)
+      (fundamental-mode))))

core/core-editor.el

@@ -1,5 +1,16 @@
 ;;; core-editor.el --- filling the editor shaped hole in the Emacs OS
 
+
+(defvar doom-large-file-size 1
+  "Size (in MB) above which the user will be propmpted to open the file literally to avoid
+  performance issues. Opening literally means that no major or minor modes are active and
+  the buffer is readonly.")
+
+(defvar doom-large-file-modes-list 
+  '(archive-mode tar-mode jka-compr git-commit-mode image-mode
+    doc-view-mode doc-view-mode-maybe ebrowse-tree-mode pdf-view-mode)
+  "Major modes which `doom/check-large-file' will not be automatically applied to")
+
 (setq-default
  ;; Save clipboard contents into kill-ring before replacing them
  save-interprogram-paste-before-kill t
@@ -88,6 +99,9 @@
       (insert linestr))))
 (advice-add #'delete-trailing-whitespace :around #'doom*delete-trailing-whitespace)
 
+;; automatically check for large files and optionally prompt to open literally
+(add-hook 'find-file-hook 'doom/check-large-file)
+
 
 ;;
 ;; Core Plugins